Diebold e-voting hack allows remote tampering

$11 microprocessor-in-middle attack is 'significant'

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Computer scientists have demonstrated a hack that uses off-the-shelf hardware to tamper with electronic voting machines that millions of Americans will use to cast ballots in the 2012 presidential elections.

The attack on the Diebold AccuVote TS electronic voting machine, which is now marketed by Election Systems & Software, relies on a small circuit board that an attacker inserts between the components connecting the touch screen of the device to its microprocessor. The $10.50 card then controls the information flowing into the machine's internal processor, allowing attackers to change votes with almost no visible sign of what's taking place.

In a video demonstration, researchers from the Vulnerability Assessment Team at the Argonne National Laboratory in Illinois showed how the card could be used to briefly kill the power to the voting machine's touch screen to temporarily black out what's displayed so voters can't see their choices being modified. Using optional hardware costing about $15, they showed how attackers can remotely tamper with machines from distances as far away as half a mile.

Anyone with a eighth grade education could construct the cards using standard tools and off-the-shelf components, said the researchers.

“This is an attack that requires less skill, so you don't have to have people hacking the software,” said David Dill, a Stanford University computer science professor and a critic of electronic voting machines, who reviewed the demonstration. “On the other hand, this does involve messing with a lot of individual machines, so it might be a little harder to change very large numbers of votes without getting caught.”

Another hurdle to be cleared is getting physical access to the targeted machines. In theory, they're subject to chain of custody procedures to prevent unauthorized modifications to the internals. But as Princeton University computer science professor Ed Felton has documented on numerous occasions (most recently here), voting machines are routinely left unattended in the days and hours ahead of election day, making it possible for attackers to tamper with them.

The AccuVote TS is used in several states, including Maryland and Georgia, although voting officials in some jurisdictions have phased out its use because the DRE, or Direct Recording Electronic, voting system typically offers no print out. That makes it particularly hard to audit results.

The Argonne researchers said they've devised an even more powerful attack against the Sequoia Advantage AVC (PDF here), a competing electronic voting machine that's now marketed by Dominion Voting Systems. Whereas the hack of the Diebold machines allows the control of data sent only from the touch screen to the microprocessor, the attack on the Sequoia device allows “bidirectional” control, they said.

The researchers went on to say they believe their attack will work on a wide variety of electronic voting machines.

“I haven't seen this particular attack described and actually carried out experimentally,” said Avi Rubin, a computer science professor at Johns Hopkins University. “Definitely, many including myself have theorized about something like this, but seeing that they actually implemented it and that it was inexpensive and relatively easy, I think, is a significant result.”

Defenders of electronic voting are quick to point out that any system used to record hundreds of millions of ballots is vulnerable to tampering. Critics say e-voting is different because it affords fewer opportunities for officials to audit votes to gauge the accuracy of the results.

“There are a million ways to hack these machines, and there are a million ways these machines can just make mistakes because they have software bugs in them,” Dill said. “You have no way of checking independently of any computer whether the vote was accurately recorded and counted.”